(1) Field of the Invention
The present invention relates to a power supply arrangement for supplying a square-wave current to a load connected to an output of the power supply arrangement, in particular a power supply arrangement in an arc furnace for producing an arc.
(2) Description of Related Art
Various power supply arrangements for supplying electric energy to an arc furnace are known in the art. Arc furnaces are used for melting steel scrap to be used for new steel products. Arc furnaces employ electric energy to melt steel scrap. The energy is converted into thermal energy which causes the steel scrap to melt. Heat produced by the arc burning between the electrode and the steel scrap is transferred to the steel scrap primarily through radiation. In an AC arc furnace, several arcs burn between the steel scrap (or the melt) and the electrode tips of the three electrodes.
A transformer of a power supply arrangement of an arc furnace adapts the energy provided by a power mains to the current and voltage required for the operation of the furnace. In arc furnaces, there is always the risk of undesirable feedback into the power mains due to non-uniform burning of the arc.